Question

What is the electric potential needed to excite He⁺ to its first excited state?

Options

• 40.8 V

• 20.4 V

• 10.2 V

• 81.6 V

Answer 1

40.8 V

Explanation:

He⁺ atom is excited to first excited level.

n₁ = 1, n₂ = 2

∆E = E₂ – E₁;

`E_n = 13.6 z^2/n^2eV = -54.4/n^2eV`

n = 1; n₂ = 2

`DeltaE = (-54.4/4 + 54.4)eV`

= 40.8 eV